jonathan Chuang
Liu Siyu

In fluid dynamics, Bernoulli's principle states that for an inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy.

Bernoulli's principle can be derived from the principle of conservation of energy. This states that, in a steady flow, the sum of all forms of mechanical energy in a fluid along a streamline is the same at all points on that streamline. This requires that the sum of kinetic energy and potential energy remain constant. Thus an increase in the speed of the fluid occurs proportionately with an increase in both its dynamic pressure and kinetic energy, and a decrease in its static pressure and potential energy.


{v^2 over 2}+gz+{poverrho}=text{constant}
{v^2 over 2}+gz+{poverrho}=text{constant}

v= velocity
g=acceleration due to gravity
z=elevation from center of gravitational mass
p=is the pressure at the chosen point
rho,
rho,
=Density of fluid

external image bernoull.jpg

http://library.thinkquest.org/2819/graphics/bernoull.jpg